Food patties of various kinds, including hamburgers, molded “steaks”, fish cakes, chicken patties, pork patties, potato patties, and others, are frequently formed in high-volume automated molding machines. Patty molding machines that can be successfully adapted to any of these food products are described in U.S. Pat. Nos. 3,887,964, 4,329,828; 3,952,478; 4,054,967; 4,182,003; 4,608,731; 4,541,143; and PCT published applications WO 99/62344, WO 2005/027666 A3 and WO 2005/027667A3 or as FORMAX® F-6, F-12, F-19, F-26, F-400 or MAXUM700® reciprocating mold plate forming machine, available from Formax, Inc. of Mokena, Ill., U.S.A.
In a typical food patty molding machine, such as disclosed in U.S. Pat. No. 3,887,964, food material is pumped into mold cavities of a reciprocating mold plate that slides between a fill position and a discharge position. The mold plate slides between a support plate or fill plate and a breather plate. The fill plate includes a fill slot which is arranged to communicate the pressurized material into the mold cavities when the mold plate is in the fill position. The breather plate includes breather orifices and an air discharge channel and functions to relieve air from the mold cavities as the food material is pressurized into the mold cavities.
An apparatus for molding food patties that have essentially uniform texture and minimal shrinkage when cooked is disclosed in U.S. Pat. No. 4,356,595. The patties also hold their shape consistently after cooking. The apparatus includes a multi-orifice plate interposed in the outlet end of a fill passage extending from a food pump to a cyclically reciprocating mold plate. The food pump is preferably controlled so that the maximum fill pressure, desirable for consistent filling of the mold cavities, is used for only a limited part of each mold plate cycle.
U.S. Pat. No. 4,372,008 also discloses a multi-orifice fill plate and uses a stripper plate slidably mounted immediately adjacent the fill plate. The stripper plate has fill openings that align one-for-one with the fill plate orifices when the stripper plate is in a fill location. Once the mold cavities are filled, the stripper plate slides transversely of the direction of mold plate movement to cut food fibers along the fill side face of the fill plate.
U.S. Pat. No. 4,821,376 describes a food patty molding machine that comprises a multi-orifice fill plate, interposed in the fill passage immediately adjacent the mold plate and a stripper plate. The stripper plate has a multiplicity of fill openings aligned one-for-one with the fill orifices as extensions thereof when the stripper plate is in its fill location. The spacings between fill openings in the stripper plate, in the direction of the stripper plate path, are such that movement of the stripper plate to its discharge location seals off the fill orifices.
The multi-orifice tooling is commercially available from Formax, Inc. of Mokena, Ill., U.S.A under the trademark TENDER-FORM®.
For both a slot fill plate and a multi-orifice fill plate, the mold plate reciprocates between a fill plate and a breather plate within a close fitting sliding tolerance. Typical “running clearances” between a reciprocating mold plate and the stationary fill plate and stationary breather plate is 0.001 to 0.003 inches
The interface between the fill plate and the mold plate is lubricated by the food material pressurized into the mold cavities which is exposed to the fill plate surface as the mold plate moves longitudinally over the fill plate. The interface between the breather plate and a mold plate is lubricated by longitudinally arranged through-slots that extend through a thickness of the mold plate and are exposed to the pressurized food material from the fill slot during at least a portion of the reciprocating cycle of the mold plate. Laterally arranged depressions or grooves on the surface of the mold plate facing the breather plate are in communication with the longitudinal through-slots and serve to distribute the pressurized food material across the width of the mold plate. This food material is exposed to the breather plate and lubricates this interface as the mold plate longitudinally slides against the breather plate.
However, the filling pressure of product against the fill side of the mold plate can reduce the running clearance opposite the filling side, the clearance between the mold plate and the breather plate, to 0.000 inch clearance. This lack of clearance removes any room for the lubricating characteristics of food such as meat to keep the metal mold plate from rubbing the metal breather plate, and can cause galling between the mold plate and the breather plate, increased wear on the mold plate and breather plate, increased driving power requirements due to increased friction between the mold plate and the breather plate, and increased leakage due to the increase clearance between the mold plate and the fill plate.
The present inventors have recognized that the longitudinal through-slots are less effective to deliver food material to the interface between the mold plate and the breather plate when using a multi-orifice fill plate because of the limited flow area of the limited number of orifices that are aligned to pass by the longitudinally arranged through-slots.
The present inventors have recognized that it would be desirable to provide a mold plate that was configured to supply an increased amount of pressurized food material to the interface between the breather plate and the mold plate for a machine that supplied food material through a multi-orifice filler plate.
The present inventors have recognized that it would be desirable to provide a mold plate that was configured to have a sufficient food material flow area between the fill plate and the breather plate through a thickness of the mold plate for both a slot fill plate and a multi-orifice fill plate.